1. Field of the Invention
This invention relates to drive systems for transmitting power to an output and more particularly, to a sectional drive system which is characterized by multiple, tapered and splined, interlocking and articulating drive segments that are characterized by exterior splines extending from a base and having specially designed drive faces, spline support faces having a larger surface area than the drive faces and matching interior spline slots located in the base. The drive segments are nested and stacked and rotate in concert as a segment string in a selected path. The path may be straight or curved, and in the latter case, the interlocking drive segments articulate to dampen drive vibration, define the chosen curve and facilitate transmission of power from a drive mechanism to an output device. The nested, stacked and articulated segment string can be interconnected interiorly by means of a cable or rod or exteriorly by floating collars and can therefore be used as a drive train in any application where transfer of power and torque are required in a straight line or at substantially any selected angle or deviation from the straight line. The sectional drive system may, for example, be used to effect horizontal drilling or coring of producing hydrocarbon intervals in oil and gas wells, utilizing the multiple, stacked and tapered, interlocking drive segments driven by a downhole drilling motor at one end of the segment string to operate a bit connected to the opposite end of the segment string. Retrieval of the segment string from the interval may typically be facilitated by a cable extending through openings in the drive segments. Consequently, the sectional drive system of this invention can be used in a downhole drilling apparatus to more efficiently effect drilling deviation in a controlled manner from a vertical or horizontal well bore and provide a primary horizontal deviation or a lateral deviation from an existing horizontal well bore.
While capable of being operated in an extremely efficient manner to permit horizontal or angular drilling of drain hole perforations in oil wells, the sectional drive system of this invention can also be implemented to transmit power from substantially any drive system to an output apparatus, drive or other system under circumstances where the power is to be transmitted in an offset or a curved line. Accordingly, the sectional drive system of this invention may be designed with extended taper or truncated thick base segments and used to transmit power from an engine, motor or other power source to automobiles, mud motors and like apparatus and equipment, as well as dental drills, robotic devices and material handling equipment, in non-exclusive particular.
2. Description of the Prior Art
Conventional techniques for effecting the transmission of power between a power source and an output under circumstances where the power is to be transmitted in an offset or curved manner, includes use of the mechanical devices as coupling mechanisms such as a universal or "CV" joint, which coupling mechanisms are well known to those skilled in the art. For example, many devices have been designed for lowering into an oil or gas well for the purpose of boring and drilling holes at right angles to the well bore at the production interval, but many problems have been encountered in using these systems. Typically, the relatively low bit rotational speed generally necessitated by using curved shafts of various design sometimes requires excessive time to achieve significant penetration, and increasing the bit rotational speed and torque load frequently causes failure of the shafts. Accordingly, these conventional horizontal drilling devices have not proved capable of sustaining the high compressive loads necessary to penetrate the well casing, concrete sheath, rock and producing interval in a well within an economical time frame without failure. Other problems have been encountered, such as bit retrieval and reduced freedom of rotation of the drilling string in such applications.
Among the directional drilling apparatus designed to achieve this function are those detailed in the following U.S. patents: U.S. Pat. No. 1,367,042, to Granville; U.S. Pat. No. 2,516,421, to Robertson; U.S. Pat. No. 2,539,047, to Arutunoff; U.S. Pat. No. 2,726,847, to McCune; U.S. Pat. No. 2,778,603, to McCune; U.S. Pat. No. 3,667,556, to Henderson; U.S. Pat. No. 3,903,974, to Cullen; U.S. Pat. No. 3,958,649, to Bull et al; U.S. Pat. No. 4,051,908, to Driver; U.S. Pat. No. 4,185,705, to Bullard; U.S. Pat. No. 4,368,986, to Cousins; U.S. Pat. No. 4,442,908, to Steenbock; U.S. Pat. No. 4,601,353, to Schuh et al; U.S. Pat. No. 4,625,815, to Spies; U.S. Pat. No. 4,658,916, to Bond; U.S. Pat. No. 4,699,224 to Burton; U.S. Pat. No. 4,880,067, to Felsma; U.S. Pat. No. 5,337,839, to Warren et al; U.S. Pat. No. 5,373,906, to Braddick; U.S. Pat. No. 5,392,858, to Peters et al; and U.S. Pat. No. 5,413,184, to Landers.
It is an object of this invention to provide an articulated sectional drive system for transmitting power linearly or in a deviated, curved or offset path to an output of selected character.
Another object of this invention is to provide a sectional drive system for transmitting power linearly or in a curved path or offset from a source of power to an output, which sectional drive system includes multiple, tapered and splined interlocking thick base drive segments that have asymmetrical splines and are stacked and nested and rotate as a segment string responsive to application of power to one end of the segment string to operate the output at the opposite end.
A still further object of this invention is to provide a sectional drive system of selected length and size, which drive system includes multiple, tapered and splined interlocking thick base drive segments that extend to a full or extended taper or are truncated at the spline taper and include a base having protruding splines with drive faces and spline support faces of unequal size, as well as spline slots or seats in the base for receiving the projecting splines. The drive segments are rotatably stacked and nested and articulate as a segment string within or without a guide path such as a tube, with the segments typically interconnected by a cable, rod or "floating" collar, for dampening drive mechanism vibration and transmitting power between a drive system and an output.
Yet another object of this invention is to provide a sectional drive system having drive segments with asymmetrical splines for drilling one or more drain holes of selected depth and angle into a producing interval of an oil or gas well to increase the flow of hydrocarbons or gas from the interval into the well bore.
A still further object of this invention is to provide a self-contained sectional drive system characterized by multiple, tapered, splined and interlocking extended taper and truncated taper drive segments that may be rotatably stacked, nested and articulated, optionally on a cable, shaft or rod as a segment string, or fitted with locking grooves and cooperating external floating collars, in a straight or curved guide path. One end of the segment string is connected to a drive apparatus such as a mud motor and the opposite end to an output such as a drill bit. The segment string may be typically rotated by the mud motor to drill a hole through well casing, concrete, damaged formations and into undamaged production formation and increase the flow of hydrocarbons into the well bore of an oil or gas well.
Still another object of the invention is to provide a transverse down-hole drilling system which is self-contained and includes multiple, cable-mounted, tapered, splined, interlocking extended-taper drive segments. The drive segments have a round base and drive faces and spline support faces of unequal area projecting from the base and companion spline slots in the base. The segments nest and rotate in concert as a segment or drive string and articulate with respect to each other in a curved path or a groove or tube. The curved path may be shaped in such a manner as to permit sufficient lateral movement to traverse a path bend at any predetermined angle with an output such as a drill bit attached to the lower end of the string and an input such as a down-hole electric or hydraulic drilling motor coupled to the upper end of the segment string for effecting rotation of the driving string and drill bit. The segments may be interconnected by means of an internal cable, a rod or shaft or multiple internally-flanged "floating" collars to define the drive string.